Two articles1,2 in the September 1993 issue of the Archives provide information regarding the visual prognosis of eyes with submacular choroidal neovascularization. In the extrafoveal study,1 the Macular Photocoagulation Study Group found that the eyes with choroidal neovascularization beneath the macula maintained, following an initial 3-month period, a median visual acuity of 20/320 during the 5-year trial. In the laser photocoagulation of subfoveal neovascularization study,2 the same study group found that the mean visual acuity of untreated control eyes with choroidal neovascularization deteriorated to 20/500 during the 4-year trial. That difference in visual acuity, after taking due consideration for the median arithmetic expression in one study and a mean average in the other, deserves explanation. If the eyes in the former trial had been used as the control group for the latter study, the effect of laser ablation of subfoveal neovascularization in age-related macular degeneration would not